A couple of points you may want to consider about the North Shore:
At the end of September there will be a lot less bugs and the leaves will be starting to turn color. The nights will be cool.
Goose Berry Falls Campground - many sites and camper spots along Lake Superior. Lots of camper use in fall.
Tettegouche Park - Lake Superior camping sites, rental cabins inland by lake or river.
Temperance River - Camping by Lake Superior, many site with electricity.